The present invention relates generally to the field of temperature controlled display devices (e.g. refrigerated cases, etc.) for storing and displaying refrigerated or frozen objects. More specifically, the present invention relates to a thermal door frame for refrigerated cases. More specifically still, the present invention relates to a door frame having improved insulation properties and/or a thermally conductive passageway to use waste heat from a lighting device to provide heat for anti-condensation purposes on an exterior surface of the door frame.
It is well known to provide a temperature controlled display device such as a refrigerator, freezer, refrigerated merchandiser, refrigerated display case, etc., that may be used in commercial, institutional, and residential applications for storing or displaying refrigerated or frozen objects. For example, it is known to provide self-service type refrigerated display cases or merchandisers having doors that are intended for operation by consumers to access refrigerated or frozen objects (e.g. food products and the like, etc.) within the temperature controlled interior space. However, such known temperature controlled display devices have a number of disadvantages. For example, the frames for such doors are typically made from metal extrusions that tend to be cooled by the interior space to the extent that condensation occurs on an exterior surface of the frame (e.g. adjacent to the door) that may lead to condensate puddle formation on the floor, or frost build-up that may prevent proper closing and sealing of the door to the frame, or may tend to cause the door and frame to freeze to one another. Such refrigerated cases are often provided with anti-condensation heaters in the form of electrical resistance heating elements mounted within the door frame extrusion to heat the exterior surface of the door frame to a temperature at or above the ambient dew point at the location of the refrigerated case (e.g. the ambient store environment, etc.). However, such known anti-condensation heaters typically consume a relatively large amount of electricity and reduce both the thermal performance and operating efficiency of the refrigerated case. By further way of example, such known temperature controlled display devices often include lighting devices within the temperature controlled interior space to illuminate the products stored therein. However, such lighting devices tend to emit waste heat that must usually be removed by the refrigeration system for the temperature controlled display device, thus placing a greater burden on the refrigeration system and further reducing the thermal performance and operating efficiency of the temperature controlled display device.
Accordingly, it would be desirable to provide a temperature controlled display device that overcomes these and/or other disadvantages.